Fury's sadness could also be explained by keeping up the charade to goad the Avengers into action.. he is a cold bastard like that and it would fit his character.
how closely do LMDs match humans? Is it possible Fury didn't find out until later?
I doubt that anyone in Shield is pulling of something like that without Fury's approval. Heck.. he was not above using some private mementos of Coulson to pull at the Avengers and get them into action. For him the ends justify the means and he can't afford to lose so what if some feelings get hurt in the process.. all that counts is the safety of Earth.
Whatever the method used ti bring back Coulson i'm fine with it.. he was, next to the main heroes, the best thing about the Marvel movie universe and i'm just happy he'll be the lead for the show.
I'd also not care if Whedon would bring back Wash and Book by whatever means if by some miracle Firefly gets on air again including just pretending that the movie never happened (and i love the movie).